The invention relates to an apparatus for processing thermoplastic synthetic plastic material that has to be recycled, comprising a first and a second receptacle for the material to be processed, in which receptacles tools circulating around vertical axes are provided for mixing and heating the material, wherein at least two tools each circulate in different levels one above the other and the material reaches the second receptacle that is connected to an evacuating means from the first receptacle through a connecting conduit, and wherein the first receptacle has above it an intake opening for the material to be processed, which intake opening is disposed at a higher level than the uppermost tools circulating in this receptacle and a discharge opening of the second receptacle is disposed at least substantially at the level of the lowermost tools circulating in this receptacle, and wherein the mouth of the connecting conduit in the second receptacle is disposed at a higher level than the tools circulating in this receptacle, and wherein the processed material is carried off the second receptacle through the discharge opening by means of at least one screw, whereby this receptacle is vacuum-tightly closed, and wherein the first receptacle is also connected to an evacuating means.
Such an apparatus is known from WO 01/21372 A1.
Another apparatus having also two receptacles through which the processed material runs in series is known from EP 632759 B1.
As a rule, such apparatus work sufficiently if the material to be processed does not make specific demands, in particular on sensitivity against air access and/or superheat and/or if a reduction of the molecule chain length should be avoided.